Liquid-sealed heat exchanger



Jan. 28, 1930. F. H. wlLLcox' 1,745,135

LIQUID SEALED HEAT EXCHANGER Original Filed Jan. 16 1925 [Federw/a H Plzwcox,

Patented Jan. 28, 1930 UNITED STATES PATENT OFFICE FREDERICK H. WILLCOX, OF CHICAGO, ILLINOIS, ASSIGNOR TO FREYN ENGINEERING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF MAINE LIQUID-SEALED HEAT EXCHANGER Original application filed January 16, 1925, Serial No. 2,763. Divided and this application filed March 26, 1927. Serial No. 178,554.

The present invention relates to combined heat interchangers and liquid seals.

The present invention is a division of the application filed by the present applicant on January 16, 1925, for improvements in blast furnace plants, which application bears the Serial No. 2,763.

The present invention is particularly applicable to blast furnace installations in which one or more blast furnaces are used, the blast furnace gas emitted therefrom being cleaned and delivered to boilers and hot blast stoves or other gas consumers. The present invention is useful in installations involving a single blast furnace or a plurality of blast furnaces operating in parallel. In installations where two or more blast fur naces are used and are delivering gas, it is, of course, necessary to shut off any blast furnace which is out of service so long as the other blast furnace or furnaces are in operation. In case of an installation involving a single blast furnace, it is desirable and practically necessary to shut off said blast furnace when operation is stopped. Valves have proven unsatisfactory in some instances, due to the fact that valves as commonly provided, unless maintained in good condition, will permit leakage of blast furnace gas, which leakage sometimes results in explosions or asphyxiation.

An object of the present invention is to provide a blast furnace installation involving one or more blast furnaces in which a blast furnace may be cut out of operation without danger from leakage of gas.

A further object is to provide a combined heat interchanger and liquid seal which is well adapted to meet the needs of commercial operation.

Further objects will appear as the descrip tion proceeds.

Referring to the drawings- Figure 1 is a diagrammatic view of a blast furnace installation employing the principles of the present invention; and

Figure 2 is a view illustrating a detail of the system shown in Figure 1.

As noted above, the present invention is useful in connection with blast furnace plants employing either one or a plurality of blast furnaces. For the purpose of simplifying the disclosure, a system employing a plurality of blast furnaces has been shown in the drawing. The principles involved in a system employing only one blast furnace will be clear from the showing of the plurality of blast furnaces.

Referring to Figure 1, the numerals 1 and 2 indicate two blast furnaces. said blast furnaces is provided with a down pipe 3, which down pipes lead to the dust catchers 44, which may have valves at the bottoms of same. Pipes 55 conduct the hot dirty gases from the dust catchers 4 1 to the gas washers, each of which is indicated as a whole by the numeral 6. Said washers 6 6 are similar to each other in construction, and at this stage of the description it may be pointed out that the "as washers illustrated in the drawing comprise the two parallel cylindrical members 7 and 8. Hot dirty gases are directed to the cylindrical member 7 of each of the gas washers, where the hot dirty gas is cleaned and delivered in washed condition to the gas main 9. Gas from the main 9 is conducted through pipes 10-10 to the hot blast stoves 11-11 and through the connection 12 to boilers indicated diagrammatically by the boiler house 13. It will be clear that when the system is operating properly the two blast furnaces 1 and 2 shown in the drawings will operate in parallel relationship to supply gas to the gas main 9. Though only two blast furnaces are illustrated, it will be understood, of course, that the present invention is applicable to any number of blast furnaces connected to the main 9 in the manner shown and described.

So long as the system is operating proper 1y, each blast furnace will supply its quota of gas to the main 9; but in the event that one or more of the blast furnaces in the battery is out of service for any reason, means must be provided for cutting said blast furnace out of connection with the remainder of the system in order to prevent the escape of gases through the blast furnace or blast furnaces which are out of operation,

Each of Valves may be provided, of course, for cutting out each blast furnace, but in view of the high temperatures encountered in service, valves, unless given constant attention, are likely to leak.

According to the presentinvention, each of the gas washers 6 serves not only to wash the gas from its corresponding blast furnace, but also acts as a seal to prevent the-back flow of gas from the system in case the corresponding blast furnace is out of operation.

A preferred form of gas washer is shown in Figure 2, which gas washer carries forward certain ideas disclosed in Patent No. 1,632,57 2, granted June 14, 1927, to the present applicant. Referring to Figure-2, the cylindrical member '7 houses the conductor 14, which conductor is preferably coaxially mounted relative to the cylindrical-member 7. Mounted midway of the length of the cylindrical member 7 is the conical wall 15, which conical wall is tightly sealed to the wall of cylindrical member 7 andto the conductor 14. The conductor 14 extends through said wall 15 to a region close to the lower extremity of the cylindrical member 7. Said wall15 divides the cylindrical member 7 into the conducting chamber or conduit 16 and. thewater-sealed chamber 17. A conduit 18 condnets-hotgases from the chamber 16-to the cylindrical member 8. The cylindrical member 8 houses gas washing means, which need not be described herein inasmuch as gas washing means are well known to those skilled in the art. The upper extremity of the cylindrical member 8 communicates with the conductor 14. Vhile passing through the gas washing means-housed within the cylindrical member8, the gases which have entered through the conduit 18 have been cooled while being washed. Said cooled gases passing out of the upper extremity of the cylindrical member 8 pass through the conductor 14, whereby the hot dirty gases in the conducting chamber 16 will communicate heat to the clean cooled gases in conductor 14, thereby raising the temperature of the gases within the conductor 14.

The chamber 17 is sealed bythe valve 19 at the bottom thereof. Said chamber 17 is adapted to contain a pool of water, the normal level of which is indicated by the numeral 20. Extending from the chamber 17 at a point above the water level 20 is the conduit 21, which leads gases to the gas main 9. \Vater may be supplied to the chamber 17 either by way of valve 19 or through any other opening (not shown). The chamber 17 provides means for holding a pool of water.

The chamber 17 not only provides means for holding a-pool of water, but also provides agasdryer or moisture eliminator. Attention is directed particularly to the fact that passing downwardly throughthe conductor 14 must reverse its direction to pass out of the outlet 21, the result is bad that a minimum ofmoisture 1S7 carried along with the gas passing out of said outlet 21.

hen the entire system is in operation the chamber17 of each of the gas washers 6'will be empty of water. Each of the blast furnaces will contribute its quota of blast furnace gases to the main 9, from which the gases maybe conducted to the gas using devices.

In the event that any of the blastfurnaces is out of operation, whereby there wouldbea tendency for gases from-thesystem to be emitted through said blast furnace, the chamber 17 will be filled with water up to the water level 20. The head of water above the opening of the conductor 14 in said chamber 17 should be chosen of a height which will prevent the escape ofgas through said water. In certain installations of the present invention which have been made, the head of water above the opening at the lower end of conductor 14 has been chosen at about 40 inches. This head has been sufficient in the installations referred to to prevent the back flow of gases from the system through the gas washer 6, dust catcher 4 and the corresponding blast furnace. The head of water will, of course, be chosen at the value suited for the condi tions encountered.

It will now be explained why the present invention is of great importance in a system involving only one blast furnace. Obviously, when the plant includes only one blast furnace there is no necessity for closing or filling the water seal or chamber 17 to prevent gas from backing up into said furnace when said furnace is out of service. However, if the furnace in a single furnace plant is shut down for any purpose, as, forexample, for changing a tuyere, cooler or plate, or for inspection, or adj ustmcnt, repairs to the hoisting machinery, banking down, blowing in or blowing out, or for any other reason, it is necessary to fill or close the water seal to prevent mixture of air andgas in the gas main of the system. In the case of such a shut down, the wind is taken off the furnace and thefurnace is almost invariably drafted back. Drafting back is done in the following manner. Vhen the furnace isoperating on one hot blaststove,its hot blast valve and cold blast valve areopenand wind is blown throughthe stoveinto the furnace. \Vhen the furnace is shut downasabove mentioned,

the hot blast valve is left open, but the cold blast valve is shut and the chimney valve is opened. The suction effect of the hot blast stove chimney thereby pulls gases within the furnace out of the furnace through the tu yeres, blow pipes, bustle pipe and hot blast main, through the stove to the chimney. This causes a vacuum in the furnace, furnace top and gas main system, and if the entire gas main system were left open from the furnace top to the burners, air would be drawn back into the system, through the open burners. If the burners are shut at this time, the condition mi ht be even worse, since the air infiltration is then slow, and instead of the air sweeping the entire system free of gas, it leaks in slowly, until an explosive mixture is had.

According to the present invention, in a system involving only one blast furnace the procedure is to close the water sealed valve at the time the furnace is stopped, that is to say-the chamber 17 is filled with Water to the water line marked 20 in Figure 2. The dust valve at the bottim of the dust catcher i is opened, and the bleeders at the top of the furnace are also opened. This permits a large quantity of cold air to sweep into the bottom of the dust catcher, up through the down comers 3, and out of the top of the furnace, thereby rapidly replacing the gas with air. At the same time the gas main system remains free of gas and unaffected by draft tending to pull air into same.

By reason of the present invention a cheap and effective seal is provided which offers no difiiculties of operation and which does not have the disadvantage of deterioration in service.

Though a preferred embodiment of the present invention has been described in detail, it will be clear that many modifications will occur to those skilled in the art. It is intended to cover all such modifications that fall within the scope of the appended claims.

lVhat is claimed is- 1. In combination, a conductor for cool moist gases, a conduit for hot dirty gases enveloping said conductor whereby the hot dirty gases may heat the cool gases in said conductor, means providing a water chamber into which said conductor projects, said conductor having an open end in said chamber, said chamber being provided with an outlet, said outlet being at a higher level than the open end of said conductor whereby when said water chamber is filled to a predetermined level with water said water will pre vent the back flow of gases from said outlet to said conductor.

2. In combination, an elongated chamber for conducting hot gases, a conductor for moist clean gas, said clean gas conductor extending throughout substantially the whole length of said hot gas chamber, said hot gas chamber being provided with a Wall at the end thereof through which said clean gas conductor extends, and means forming a receiving chamber with which said clean gas conductor communicates, said receiving chamber being adapted to hold a pool of water and having an outlet above the normal level of said water whereby to seal said conductor against the fiow of gas from said outlet through said chamber to said conductor.

3. In combination, an elongated member having a partition midway of its length providing two chambers, means for directing hot gases to one of said chambers, a conductor mounted interiorly of one of said chambers for conducting clean cool gas into thermal communication with the hot gases of said one chamber, said conductor being mounted to extend through said partition to direct clean gas to said other chamber, said other chamber having an outlet mounted at a higher level than the orifice from said conductor, said other chamber being adapted to hold a pool of water whereby to seal said mechanism against the back flow of gases from said outlet through said chamber to said conductor.

Signed at Chicago, Illinois, this 23 day of March, 1927.

FREDERICK I-I. WVILLCOX. 

